Introduction Platinum Resistance Elements

Platinum resistance elements are temperature sensors for resistance thermometers. They cannot generally be used in their basic element form but must be built into some type of assembly which will enable them to withstand the various environmental conditions to which they will be exposed when used. It should be noted, however, that they will always measure the "mean value" of the temperature over their total winding or sensitive length.

Gekon Trading offer three basic types
of Platinum Resistance Elements:

Thin film elements have a sensitive platinum film deposited onto the ceramic former. Thin films are available in smaller dimensions and offer the possibility for higher nominal resistance values.

Wire wound ceramic elements consist of a ceramic body with the heat sensitive resistance wire encapsulated into longitudinal bores. Wire wound glass elements have the resistance winding solidly embedded in a glass former. This makes the elements (wire wound or thin film) suitable for extreme operating conditions.

Gekon Trading also offers Slot Type resistance thermometers for temperature detection and monitoring of stator windings in electrical machines and generators.

Gekon Trading produces a wide range of element types that offer different measuring ranges, various shapes and sizes and a variety of the number of resistance circuits carried on the same body.

Reliable temperature measurements with platinum resistance elements requires experience in assembly procedures and expertise in the choice of materials used. Gekon Trading offers a wide range of ready to use resistance thermometers to meet the needs of our customers world wide.

Tolerances

The Tolerances conform to the International Industrial Standard IEC 751 (identical with DIN IEC 751) for the temperature range -200°C to +850°C. The values quoted between -250°C and -200°C have been derived from Gekon Tradings own test results.

The platinum resistance elements are all supplied according to Class B tolerance (DIN IEC 751).

Δt [°C] = ± ( 0,3°C + 0,005 [t] )

For applications requiring exceptional accuracy, Class A tolerance is available on special order.

Δt [°C] = ± ( 0,15°C + 0,002 [t] )

Not all of the Gekon Trading element types can be supplied within Class A tolerance. It is recommended that you speak with a Gekon Trading representative before placing an order.

Many applications require the use of special tolerances and Gekon Trading can supply the following on special orders:

±0,15°C by 0°C or ±0,1°C by 0°C

For temperatures other than 0°C, only Class B tolerance standards can be guaranteed. Please contact a Gekon Trading representative for information on standard values.

For applications not requiring the levels of accuracy mentioned above, Gekon Trading has available elements with wider tolerances at highly competitive prices. Some examples are:

±0,45°C by 0°C or ±1,5°C by 0°C

A Gekon Trading representative can recommend a variety of elements with non-standard tolerances at a given temperature or within a more restricted temperature range.

Self Heating

Resistance elements through which a current flows are slightly heated by the current. The magnitude of the self heating error depends on the electrical energy input (N = I² x R), the volume of heat dissipation and the apparatus constant (EK), the self heating co-efficient. The self heating coefficient for each resistance element when used in water or air is shown by clicking on the resistor icon. Self heating can be calculated by the following formula:

Δt = N / EK

Δt = Self heating in K,
N = Electrical energy input to resistance element in mW,
EK = Self heating co-efficient in mW / K.

For general information on resistance element self heating, the current in mA is stated for each resistance element at which 0.1 K self heating occurs in a water flow at ambient temperature.

Long Term Stability

Compared with other temperature sensors, platinum precision resistance elements posses good long term stability at the higher temperature ranges.

Supply Range

The standard Gekon Trading element types are stock items for fast delivery to customers and are offered at competitive prices. Gekon Trading also offers non-standard versions for special applications.

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GEKON Trading GmbH

John-F-Kennedy-Str. 88 - D-63457 Hanau

+49 (0) 6181 956-270 -